1. Field of the Invention
The present invention relates to an article transport facility comprising an article transport vehicle that is capable of traveling along a travel rail provided on a ceiling side and an article storage including a plurality of storage units, the storage units being arranged in a vertical direction and being capable of storing articles that are transported by the article transport vehicle, wherein the article storage is located to a side of the travel rail in plan view and includes a take-in portion for receiving articles to be stored in the storage units from the article transport vehicle and a take-out portion for delivering articles to be retrieved from the storage units to the article transport vehicle.
2. Description of the Related Art
In article transport facilities such as one described above, a travel rail is provided on the ceiling side such that the rail extend by way of or along a plurality of article processors. And article transport vehicles include a grip portion for gripping an article such that the grip portion can be vertically moved or raised and lowered. And the article transport vehicles transport articles among the plurality of article processors by traveling along the travel rail provided on the ceiling side and by vertically moving the grip portion. In addition, an article storage having two or more storage units that are arranged in the vertical direction is provided for, for example, temporarily storing articles transported by the article transport vehicle. The article storage includes a take-in portion for receiving articles to be stored in the storage units from the article transport vehicles and a take-out portion for delivering articles stored in the storage units to the article transport vehicles. And thus, the articles are transferred between an article transport vehicle and the article storage through the take-in portion and the take-out portion.
Examples of conventional article transport facilities include a facility having two transport conveyers that are capable of transporting articles between a transfer position located outside an article storage and under the travel rail, and an inside position located inside the article storage with the two transport conveyers functioning as the take-in portion and the take-out portion. (See, for example, JP Publication of Application No. 2004-10250, hereinafter referred to as “Patent Document 1”). In the facility described in Patent Document 1, an article transport vehicle is configured to be able to transfer an article to or from transfer positions located below the travel rail and on transport conveyers by vertically moving a grip portion. Thus, the articles are transferred between the article transport vehicle and the transport conveyers at the transfer positions of the transport conveyers. And two transport conveyers are provided and arranged next to each other in the travel direction of the travel rail with one transport conveyer provided to function as a take-in portion for receiving articles in its transfer position from the article transport vehicle and the other transport conveyer provided to function as a take-out portion for delivering articles in its transfer position to the article transport vehicle.
In another conventional article transport facility is one in which no such transport conveyers are provided and in which storage units of the article storage are used as a take-in portion and a take-out portion. (See, for example, JP Publication of Application No. 2009-173396, hereinafter referred to as “Patent Document 2”). In the facility described in Patent Document 2, an article transport vehicle is configured not only to be able to vertically move the grip portion but also to be able to slidingly move the grip portion along the lateral direction of the travel rail. Thus, the article transport vehicle is configured to be able to transfer an article to or from a transfer location located below the travel rail by vertically moving the grip portion, and to be able to transfer an article to or from a transfer location located to one side of the travel rail by vertically moving the grip portion after the grip portion has been slidingly moved along the lateral direction of the travel rail. And a storage unit, located in the top portion of the article storage that is provided close to the travel rail such as a location to one side of the travel rail, is configured to be used as a take-out portion (or a take-in portion). In addition, a storage unit, located one level below the top portion of the article storage is configured to be moved horizontally between a transfer position located outside the article storage and below the travel rail and a storage position inside the article storage. And this storage unit located one level below the top portion of the article storage is configured to be used as a take-out portion (or take-in portion). Thus the article transport vehicle transfers an article to the storage unit that is located one level below the top portion of the article storage and that functions as a take-in portion by vertically moving the grip portion, and transfers an article to the storage unit that is located in the top portion of the article storage and that functions as a take-out portion by vertically moving the grip portion after the grip portion has been slidingly moved along the lateral direction of the travel rail.
When transferring an article between the article transport vehicle and the article storage, the article transport vehicle may have to perform, in succession, a storage operation in which an article is transferred to the take-in portion and a retrieval operation in which an article is transferred from the take-out portion. In the facility described in Patent Document 1, the article transport vehicle firstly transfers the article to the transfer position of the transport conveyer that functions as the take-in portion by traveling to a stop position that corresponds to the transport conveyer that functions as the take-in portion and by vertically moving the grip portion to perform the storage operation. Next, the article transport vehicle transfers the article from the transfer position of the transport conveyer that functions as the take-out portion by traveling to a stop position that corresponds to the transport conveyer that functions as the take-out portion and by vertically moving the grip portion to perform the retrieval operation. As such, in the facility described in Patent Document 1 described above, because the transport conveyer that functions as the take-in portion and the transport conveyer that functions as the take-out portion are spaced apart in the travel direction of the travel rail, the article transport vehicle must travel to the stop position corresponding to the transport conveyer that functions as the take-out portion after performing the storage operation. The travel takes additional time, which leads to reduction in transporting efficiency.
In the facility described in Patent Document 2, the storage units of the article storage are used as the take-in portion and the take-out portion. And the storage unit that functions as the take-in portion and the storage unit that functions as the take-out portion are arranged such that they overlap in the vertical direction. Therefore, the position at which the article transport vehicle transfers the article to the storage unit that functions as the take-in portion coincides, in the travel direction of the travel rail, with the position at which the article transport vehicle transfers the article to the storage unit that functions as the take-out portion. As such, the article transport vehicle can perform the retrieval operation without having to travel after performing the storage operation; thus, the problem of reduction in transporting efficiency can be avoided.
However, in the facility described in Patent Document 2, because the storage unit of the article storage is used as the take-out portion (or take-in portion), the installation location of article storage is limited to a location close to the travel rail, such as a position located to a side of and close to the travel rail. That is, in the facility described in Patent Document 2, articles are transferred to the storage unit of the article storage that functions as the take-out portion (or take-in portion) by slidingly moving the grip portion along the lateral direction of the travel rail. Therefore, the installation location for the article storage is limited to within the area in which the grip portion can be slidingly moved from the travel rail; thus, the article storage cannot be installed in the position away from the travel rail.
In addition, in the facility described in Patent Document 2, because the storage units located in the top portion and one level below the top portion of the article storage are used as the take-in portion and the take-out portion, the take-in portion and the take-out portion are located at high locations in the article storage. Therefore, a human operator needs to perform work on the take-in portion and the take-out portion that are located high above the ground, for example, to service the storage units that are used as the take-in portion and the take-out portion, which makes it difficult to service these portions.
The present invention was made in light of this point, and its object is to provide an article transport facility which can shorten required time to improve transporting efficiency even when performing, in succession, a storage operation in which an article is transferred to the take-in portion and a retrieval operation in which an article is transferred from the take-out portion and without limiting the installation location for the article storage to provide greater freedom in the location of the article storage.